Sudden cardiac death (SCD) occurs in approximately 400,000 people in the U.S. each year. Half of all coronary heart disease deaths are sudden and unexpected; these include people at risk of dying from SCD while they are awaiting a heart transplant or immediately after they survive a heart attack. SCD is a direct result of cardiac arrhythmia (cardiac arrest) and may be reversible if responded to promptly through the administration of at least one electrical shock to the victim's heart. If left uncorrected, the irregular heartbeat can lead to irreversible brain damage and even death. It has been determined by the American Heart Association that for every minute that a person experiences cardiac arrhythmia without being defibrillated, the chance of survival decreases by about 10 percent.
Defibrillators have been used for years to restore normal heart rhythm to victims experiencing cardiac arrhythmia, these include external and implantable defibrillators. However, those patients who typically benefit from such implantable defibrillators face an increased risk of complications resulting from the implantation surgery. Thus, these patients are usually confined to extended hospitalization so that they may receive prompt defibrillation, if necessary. Doctors sometimes recommend home defibrillators for patients with chronic heart conditions (e.g., heart disease).
Portable external defibrillators have been in use for years and depend on bystanders to successfully administer the electrical therapy to the victim. Recently the U.S. Food and Drug Administration approved the use of a wearable cardioverter defibrillator available from Lifecor, Inc. (Pittsburgh, Pa.), see U.S. Pat. No. 5,741,306. This defibrillator is strapped to the lower chest and shoulders of the user and must be continuously worn in order to detect and impart electrical therapy in response to cardiac arrhythmia in the patient. However, this wearable defibrillator is bulky and cumbersome, reducing the likelihood the user will continuously wear the device, thereby decreasing its effectiveness.
A basic defibrillator consists of a power source (i.e., battery), microprocessor, and electrodes interconnected by electrical circuitry. The defibrillator can include a cardiac module which utilizes the same or different electrodes than the defibrillator. These electrodes sense the heart's rhythm and the microprocessor interprets the rhythm to determine if a shock is needed to treat fibrillation. If the heart is in fibrillation, the defibrillator will charge in preparation to deliver the shock. The electrodes deliver an electric shock that travels through the victim's chest to stun the heart, momentarily stopping all activity. This momentary inactivity gives the heart a chance to restart normal electrical activity and resume beating. A successful defibrillation is one that causes the fibrillation to be converted to another rhythm, even if this rhythm is unshockable.
Public automated external defibrillators (AEDs) have been in use for years. Most AEDs have been designed to require little to no training to operate. These AEDs are found in public places where groups of people congregate, such as, offices, airports, restaurants, hotels, schools, etc. Public AEDs are usually mounted inside brightly colored, protective cases to make them highly visible to the community. When these protective cases are opened and defibrillator removed, often an alarm will indicate their removal. However, most of these alarms do not summon emergency services and only some AEDs include a phone to contact emergency personnel. Those AEDs that do include a telephone depend upon fact that the person making the call is aware, or capable, of determining the exact location of the victim.
There are two types of automated external defibrillators: semi-automatic and fully-automatic. Both types approved in the United State will prompt and guide the operator through the use procedures visually, audibly or both. The semi-automatic AEDs will instruct the operator to stand clear of the victim and to push a shock button to defibrillate. The fully-automatic units will warn the operator to stand clear and then deliver the shock automatically without the user having to push a button.
Wireless communication devices (cellular telephones, PCS, personal digital assistants, pagers, etc.) have become virtually ubiquitous in many societies. These wireless devices are currently being developed for use over a wide swath of health care applications. These include, albeit not limited to, patient monitoring, equipment monitoring, telemedicine, prescriptions and patient record keeping. Given their ready accessibility it makes sense to integrate these wireless communication devices with equipment capable of providing emergency medical capabilities.
What has been heretofore lacking in the art is a wireless telecommunication device capable of normal everyday communication which is also capable of recognizing a cardiac irregularity and, if deemed necessary, defibrillates the victim. The present invention is particularly ideal for patients at risk for sudden cardiac arrest and those who are not candidates or refuse an implantable defibrillator. The device utilizes a power supply that can retain a sufficient amount of electrical energy to power the defibrillator yet is small enough in both size and weight to be easily carried on one's person or inside a handbag.